The present invention relates generally to a controller for regulating the temperature of an electric machine, and in particular to a controller which regulates the temperature of an electric machine by adjusting the motor's output based on feedback of a measured motor temperature.
When an electric motor is operated at peak power for an extended period of time, power dissipation is high and the temperature of the motor rises rapidly. It is important to protect an electric motor from overheating to prevent the motor from failure.
It is known in the prior art to control the motor output, such as the commanded torque, based on a measured motor temperature. However, prior art methods, such as the one disclosed in U.S. Pat. No. 5,227,703, reduce the commanded torque by a fixed amount resulting in an open loop control scheme that may not adequately prevent the temperature from rising too high. What is needed is an effective method for regulating temperature of a motor as a protection system for electric motors used in industrial and automotive applications.